In recent years, along with an increase in luminance of semiconductor light emitting devices, use of semiconductor light emitting devices as a light source of a lighting apparatus has been examined.
For example, as shown in FIG. 1, a lighting apparatus 100 disclosed in Japanese Laid-Open Patent Application Publication H09-288460 (hereinafter, referred to as the “lighting apparatus of Conventional Example 1”) is formed by mounting a plurality of round semiconductor light emitting devices 102 in a matrix on a control body 101. Individual semiconductor light emitting devices 102 are all together supported by a rubber support 105 having a plurality of through-holes 104 into which lens portions 103 are inserted.
In addition, as shown in FIG. 2, a lighting apparatus 110 disclosed in Japanese Laid-Open Patent Application Publication 2002-299694 (hereinafter, referred to as the “lighting apparatus of Conventional Example 2”) is formed by mounting a plurality of semiconductor light emitting devices 112 in a matrix on a metal substrate 111 and covering a mounting surface 113 of the substrate 111 with a resin layer 114 to thereby seal the semiconductor light emitting devices 112. Here, the mounting surface 113 is coated with a high reflectance material.
Furthermore, as shown in FIG. 3, a lighting apparatus 120 disclosed in Japanese Laid-Open Patent Application Publication H11-340517 (hereinafter, referred to as the “lighting apparatus of Conventional Example 3”) has a reflective member 123 on which a reflecting surface 122 for guiding, in a direction of drawing out the chief ray, light emitted from a semiconductor light emitting device 121 is formed. The semiconductor light emitting device 121 and reflective member 123 are individually attached to a mounting surface 125 of a substrate 124, and sealed by a resin layer 126 covering the mounting surface 125.
However, the lighting apparatuses 100, 110 and 120 above have various problems in terms of luminance, heat release characteristics, detachment of the resin layer and so on.
That is, as to the lighting apparatus 100 of Conventional Example 1, the luminance is insufficient since part of each lens portion 103 is covered by the rubber support 105, which intercepts light emitted from a light emitting element (not shown). In addition, although the rubber support 105 fitted firmly to the lens portions 103 serves as a heat-releasing member, the heat release effect is not as sufficient as a metal support, because it is made of rubber.
Since the lighting apparatus 110 of Conventional Example 2 does not have a reflecting plate, light emitted in parallel to the mounting surface 113 cannot efficiently be guided in a direction of drawing out the chief ray, which results in insufficient luminance.
The lighting apparatus 120 of Conventional Example 3 cannot efficiently release heat generated in the semiconductor light emitting device 121 because the space between the semiconductor light emitting device 121 and the reflective member 123 is entirely filled with resin. In addition, due to difference in coefficient of thermal expansion, the resin layer 126 is likely to be detached from the reflective member 123 and the substrate 124. On top of this, a contact area between the resin layer 126 and substrate 124 is small due to the presence of the reflective member 123. Therefore, the adhesion between the resin layer 126 and substrate 124 is reduced, which makes the detachment occur more readily.
The present invention has been made in view of the above-stated problems, and aims at offering a lighting apparatus which (i) has high luminance, (ii) causes sufficient heat release, and (iii) is less likely to cause the detachment of the resin layer.